Egypt is a country of tremendous land resources but limited water resources. The area of cultivated land is hardly exceeding 31,500 km2 or only 3.15% of the gross area. The river Nile is the main source of water in Egypt. The share of Egypt in the flow of the river Nile is at least 55.5 billion m3/year. Due to the huge increase in population growth the per capita share of productive land has fallen from 0.28 ha in 1898 to 0.05 ha in 1999. Not only the per capita share of land is going down; the per capita share of water is also falling sharply. This share of 850 m3 per capita per year is already below the so-called “water-poverty” line of about 1,000 m3 per capita per year. It will be even further reduced to an expected amount of 555 m3 per capita per year by 2025.
In the recent years the Government established large scale agricultural projects in order to compensate the population growth. Expansion of irrigated agriculture has to be predominantly realized by increasing the water use efficiency. In Egypt, the dominant irrigation method is surface irrigation, which covers approximately 83% of the irrigated areas. The rest lies under sprinkler (12.5%) and drip (4.5%).
Surface irrigation or gravity methods are generally characterized by a low application efficiency. One opportunity to increase the efficiency of surface irrigation is to convert it to sprinkler or drip. Converting surface irrigation systems to sprinkler or drip is highly expensive for a country like Egypt. Another option to increase the efficiency of surface irrigation systems is to convert the traditional irrigation method to surge flow irrigation. Surge flow irrigation is the intermittent application of water to furrows or borders in a series of relatively short on and off time periods.
Varlev (1971) introduced the concept of surge flow irrigation in Bulgaria as a method for improving the uniformity of moisture distribution along the furrow. Stringham and Keller (1979) have essentially developed this irrigation method at Utah State University. Since then, it is widely applied in large areas in many countries like several states of the USA, Australia and Portugal. Large sizes and long furrows characterize the farms of these areas. The length of the furrows ranges from 300 m to 1700 m, especially the very long furrows are used in the USA. The main objective of the introduction of surge flow irrigation is to increase the efficiency and the productive use of water. Researches indicate that surge flow irrigation helps to increase application efficiency, increases crop production and saves water. Information about the proper stream size, initial on-time and cut–back phase became known. Moreover, guidelines for using surge flow irrigation in long fields have been established. Application of surge flow irrigation under small farm sizes and short field conditions is still not known.
This study has been carried out to demonstrate the applicability of surge flow irrigation under short field conditions as they prevail in Egypt. To study the effect of surge flow irrigation two sets of field experiments have been established at two different locations. The first set of the experiments has been carried out in the Tunnel experimental plot of the Irrigation and Water Engineering Group, Wageningen University, the Netherlands. The aim of the experiments was to get familiar with surge flow irrigation and to operate it manually as well as to select the treatments, which can be applied under Egyptian conditions. The Tunnel contained two soil types namely, sandy clay and sandy clay loam. The second set of the field experiments has been carried out in two different locations in Assiut, Egypt. The first location is classified as clay soil and was situated at the Agriculture Experimental Station, Assiut University. The second location is classified as sandy soil. It was situated at the Assiut University Experimental Station for desert lands, El-Wadi El-Assuity, Assiut. It was a new place under reclamation and it was the first time for water to touch this land. The aim of the experiments in Egypt was to apply surge flow irrigation under the prevailing Egyptian conditions which are short fields and arid conditions, to select the best treatments which can be used for such conditions and to optimize water use as well as to establish guidelines for using surge flow irrigation efficiently under short field conditions.
The lay-out of the field experiments was the same in the Netherlands and Egypt except for the slope, furrow width and a slight difference in some discharges. Under the Netherlands conditions the slope was 0.0058 m/m and furrow width 0.75 m for both soil types. The discharges were 0.46, 0.76 and 0.92 l/s for sandy clay soil meanwhile they were 0.76, 0.92 and 1.29 l/s for sandy clay loam soil. Under the Egyptian conditions the furrow width was 0.70 m for both soil types. The slope of clay soil was 0.0024 m/m and the discharges were 0.46, 0.74 and 0.90 l/s. Meanwhile, the slope of sandy soil was 0.004 m/m and the discharges were 0.73, 1.0 and 1.4 l/s. The furrow length in the experiments was 70 m for all soil types in the Netherlands and Egypt. The furrows had a blocked end. To monitor the advance and recession time, five points were established along the furrows, namely at 0 L, 1/4 L, 1/2 L, 3/4 L, and 1 L. The distance between two consecutive points was 17. 5 m. To study the effect of surge flow irrigation on the water distribution along the furrow, the soil moisture content was measured at three locations, namely at the beginning, middle and end of the furrows. In each location three points in a vertical were measured at a depth from 0.0 – 0.2 m, 0.2 – 0.4 m and 0.4 – 0.6 m below surface under the Netherlands conditions. Meanwhile, they were 0 - 0.1 m, 0.1 - 0.3 m and 0.3 - 0.7 m under Egyptian conditions.
To investigate the water content distribution in the cross-sections, one furrow for each soil type was selected for the measurement of the water content at three different verticals in that cross-section, namely at the furrow bottom, at the middle of the side slope and on the outside ridge. The water content in the soil was measured by different methods according to the availability of the equipment in each location. The Time Domain Reflection (TDR) was used in both soil types under the Netherlands conditions. The profile probe method has been used in clay soil and the gravimetric method in sandy soil under the Egyptian conditions. The gravimetric method which was used in the sandy soil was due to the gravel, which hampered the installation of the fiberglass tubes. The cycle times and ratios were the same for all soil types under the Netherlands and Egyptian conditions. Two cycle times have been investigated, namely 16 and 24 minutes. Three cycle ratios were tested under each cycle time, 1/4, 1/2, and 3/4 for the cycle time of 16 minutes and 1/3, 1/2 and 2/3 for the cycle time of 24 minutes. The different cycle ratios were applied to study the effects of off-time on the water distribution along the furrow. Based on the discharges, cycle time and cycle ratio large numbers of alternatives of surge flow irrigation have been investigated beside the continuous flow for each soil type. The alternatives for surge flow irrigation during this investigation were related to the objectives of this research and have been chosen on basis of water management guidelines as presented in the literature. Some selected alternatives for a number of discharges have been repeated during the second and third irrigation to study the effect of surge flow irrigation during subsequent irrigations under the Netherlands conditions.

The obtained results can be summarized as follows:
- The research shows that surge flow irrigation offers the potential of increasing the distribution uniformity, thereby increases the effective use of water in surface irrigation systems. The benefits ascribed to surge flow irrigation result from a reduction in the infiltration rates;
- Infiltration characteristics of the soil are major factors in the design of field irrigation systems. Reduced infiltration can lead to a faster water advance, thus leading to a reduction of deep percolation. The irrigation time is shortened and the water volume required for completion of the irrigation is reduced, which will improve the irrigation uniformity;
- Surge flow irrigation is applicable in different soil types under short field conditions. It can save a large amount of water ranging from 15% to 35% during the first irrigation and from 12% to 15% overall the growing season based on the soil type, crop and the best combination of discharge, cycle time and cycle ratio;
- The recommended discharges which maximize the water saving and which can be used under short field conditions are different for each soil type. Based on the obtained results the discharges of 0.46, 0.76, 0.74 and 1.0 l/s were the recommended discharges for sandy clay, sandy clay loam, clay and sandy soils respectively;
- Comparison of the results of cycle times (16 and 24 minutes) indicated that both of them can be used but a 24 minutes cycle time is better than 16 minutes especially under the Egyptian conditions because it was dominant in both soil types, clay and sandy soils;
- The cycle ratio which advances the water to the lower end of the furrow as fast as possible is different due to the soil type and the discharges. The cycle ratio of 1/3 may be recommended because it is the best case for half of all discharges used under the Netherlands and Egyptian conditions. Operating surge flow irrigation with high sophisticated surge valve leads to any possible cycle ratio meanwhile operating it manually leads only to one option, which is 1/2 cycle ratio;
- A proper slope configuration is required for getting a good moisture distribution along the furrow although it has a little effect on surge flow irrigation. In general, gentle slopes are required for fine textured soils, moderate slopes can be used in medium textured soils and steep slopes are recommended for coarse textured soils;
- The best time for using surge flow irrigation with its maximum benefits is at the first irrigation at the beginning of the season. It can also be used during subsequent irrigation but with less effect compared to the first irrigation in coarse textured and tilled soils;
- Comparison of the predicted water advances by SIRMOD III in all the experiments with measured water advances indicated that with a good representation of the infiltration parameters, surge flow irrigation under short field conditions can be successfully simulated, designed and evaluated. Management alternatives of discharges and cycle times can be obtained by using SIRMOD III model;
- Surge flow irrigation can be considered environmental friendly. It tends to decrease the infiltration rate and consequently decreases the deep percolation. As the deep percolation is decreased all fertilizers and pesticides moving downward will be decreased; kept in the upper part of the soil; available for the plant use and far away form the groundwater table; thus the groundwater will be protected against the main source of agricultural pollution;
- Model results show that the same amount of yields can be produced under surge flow irrigation with less supply compared to continuous flow, or higher crop yields can be produced under surge flow irrigation compared to continuous flow when the same gross irrigation supply is used.
- Surge flow irrigation is an effective irrigation method to save water and/or to increase crop production in short field conditions like those that prevail in Egypt.